Chain/sprockets

Z1, KZ900 and the early KZ1000's to 1980 (and 81 cop bike) use a 13-tooth spline front sprocket.  18T/42T 530 is the equivalent to the OEM 15T/35T 630 sprockets.

530 chain is 5/8 pitch, 630 is 3/4" pitch (6/8") - to convert 630 to 530 divide by 5 and multiply by 6.  The same is true with chain length.  92 link becomes 110 link.

When I got my KZ750 LTD I think the previous owner/mechanic ordered a rear sprocket by looking it up, instead of checking what was on the bike. A KZ750 twin uses a 38T rear sprocket, which is what mine had along with the original 13T front sprocket. It was a rocket off the line, but I was in 5th most of the time because the gearing was so low.

I changed to a 530 chain/sprocket set. I went with a 16T front (part number JTF513 -16), and a 38T rear (part number JTR488 -38) using JT sprockets, and a DID chain (DID50VX114).

There is probably enough space to go one sprocket up on the front (to a JTF513 -17), I wouldn't try going any higher, there isn't much room there.